Electroluminescence in light emitting polymers featuring deaggregated polymers

ABSTRACT

In general terms, the present invention includes a light emitting polymeric material the light emitting polymeric material capable of producing electroluminescence upon being provided with a flow of electrons, the light emitting polymeric material comprising a plurality of polymeric chains comprising polymeric chains each having substituent moieties of sufficient number and size and extending from the polymeric chain and about a substantial portion of the circumference about the polymer chain so as to maintain the polymeric chains in a sufficiently deaggregated state (referred to herein as a “strapped” polymer), so as to substantially prevent the redshifting of the electroluminescence and the lowering of light emission efficiency of the electroluminescence.

[0001] The present application is a divisional application of U.S.patent application Ser. No. 08/901,888, filed Jul. 29, 1997, whichclaims priority to U.S. Provisional Application No. 60/023,071, filedAug. 2, 1996, both of which are hereby incorporated by reference intheir entirety herein.

TECHNICAL FIELD OF THE INVENTION

[0002] The present invention is in the field of light-emitting polymersand light emitting devices produced therefrom.

BACKGROUND OF THE INVENTION

[0003] Conjugated polymer based light-emitting devices have become anextensive area of academic and industrial research since the report ofelectroluminescence (EL) in poly(phenylene vinylene) (PPV) in 1990 [1].

[0004] A great number of different conjugated polymers have been foundto exhibit EL including PPVs [1-3], poly(phenylphenylene vinylene) [4],polyphenylenes [5-7], polythiophenes [8-9], polyquinolines [10],polypyridines [11-12], poly(pyridyl vinylenes) [12-14] and manycopolymers of these materials.

[0005] In addition to many different materials, numerous configurationshave been used to change and improve device performance. For instance,the use of additional layers to improve device efficiency has been knownfor some time [2,15]. Inserting a hole-transport (electron blocking)layer between the anode and emitting polymer or an electron-transport(hole-blocking) layer between the cathode and emitting polymer cangreatly improve efficiency by confining the majority carrier to theemitting layer. A well known hole-transport (electron blocking) layer ispoly(vinyl carbazole) (PVK) which has a large band gap (3.5 eV) and isitself luminescent [16-18].

[0006] Despite these advances there remains a need for improvements inthe electroluminescence performance of light emitting polymers.Particularly, there remains a need to improve the performance ofexiplex-forming bilayer devices so as to reduce or eliminate theredshifting believed to be associated with the aggregation of polymericchains within the emitting polymer.

[0007] It is a goal of the present invention to produce light emittingpolymer and light emitting polymer devices made which give lightemissions having reduced redshifting.

[0008] In view of the present disclosure or through practice of thepresent invention, other advantages may become apparent.

SUMMARY OF THE INVENTION

[0009] In general terms, the present invention includes a light emittingpolymeric material the light emitting polymeric material capable ofproducing electroluminescence upon being provided with a flow ofelectrons, the light emitting polymeric material comprising a pluralityof polymeric chains comprising polymeric chains each having substituentmoieties of sufficient number and size and extending from the polymericchain and about a substantial portion of the circumference about thepolymer chain so as to maintain the polymeric chains in a sufficientlydeaggregated state (referred to herein as a “strapped” polymer), so asto substantially prevent the redshifting of the electroluminescence andthe lowering of light emission efficiency of the electroluminescence.

[0010] It is preferred that the polymer of the present inventioncomprises polymeric chains selected from the group consisting ofalternating and random copolymers, having comprising the structure:

[0011] wherein m is the degree of polymerization; Y is selected from thegroup consisting of —CH₂, O, S, CO and NR₂ wherein R is an alkyl groupcontaining 1 to 16 carbon atoms; A and C are independently selected fromthe group consisting of (CH₂)_(n), (CH₂CH₂O)_(n), (CH₂ CH₂O)_(n)NRwherein R is an alkyl group containing 1 to 16 carbon atoms, and arylgroups having 6 to 14 carbon atoms; B is selected from the groupconsisting of (CH₂)n, aryl groups having 6 to 14 carbon atoms, andcalixarene having 18 to 200 carbon atoms; wherein u may be of a valueindependently selected from the group 1 to 6, inclusive; wherein w maybe of a value independently selected from the group 1 to 6, inclusive;wherein n may be of a value independently selected from the group 0 to6, inclusive; and wherein Z may be a structure selected from the groupconsisting of:

[0012] wherein R is an alkyl group containing 1 to 16 carbon atoms,wherein Y is selected from the group consisting of —CH₂, O, S, CO andNR₂ wherein R is an alkyl group containing 1 to 16 carbon atoms; B isselected from the group consisting of (CH₂)_(n), aryl groups having 6 to14 carbon atoms, and calixarene having 18 to 200 carbon atoms; wherein umay be of a value independently selected from the group 1 to 6,inclusive; and wherein w may be of a value independently selected fromthe group 1 to 6, inclusive.

[0013] The electron transporting polymer may include polymeric chainsselected from copolymers having the structure:

[0014] Some specific examples of polymers used in the present inventioninclude:

[0015] The light emitting polymeric material may also be used in singlelayer, bilayer or other multiple layer devices, using the polymericmaterial of the present invention. In the case of a single polymericlayer device, the polymeric material of the present invention may beused as the electron transporting/electron blocking layer. In the caseof a bilayer or multi-layer devices, the polymeric material of thepresent invention may be used as the electron transporting layer inconjunction with an electron blocking layer of another appropriatepolymer, such as might be selected from the group consisting ofpoly(vinylcarbazole).

[0016] The present invention also includes a light emitting devicecomprising a light emitting polymeric material according to the presentinvention in all of its embodiments, and a source of electrical currentso as to supply the light emitting device with a flow of electronscapable of producing electroluminescence from the device.

[0017] The present invention also includes a light emitting polymericmaterial capable of producing electroluminescence upon being providedwith a flow of electrons, where the light emitting polymeric materialcomprises: a plurality of rotaxanes each comprising a polymeric chainhaving at least one ring extending about the circumference of thepolymeric chain so as to maintain the rotaxanes in a sufficientlydeaggregated state so as to substantially prevent the redshifting of theelectroluminescence and the lowering of light emission efficiency of theelectroluminescence.

[0018] It is preferred that the light emitting polymeric material isfurther provided with a layer of an electron blocking polymer. It ispreferred that the electron blocking polymer is poly(vinylcarbazole).

[0019] It is preferred that at least one polymeric chain of the rotaxaneis selected from the group of alternating and random copolymers havingat least one structure selected from the group consisting of:

[0020] wherein R is an alkyl group containing 1 to 16 carbon atoms;wherein Y is selected from the group consisting of —CH₂, O, S, CO andNR₂ wherein R is an alkyl group containing 1 to 16 carbon atoms; B isselected from the group consisting of (CH₂)_(n), aryl groups having 6 to14 carbon atoms, and calixarene having 18 to 200 carbon atoms; wherein umay be of a value independently selected from the group 1 to 6,inclusive; and wherein w may be of a value independently selected fromthe group 1 to 6, inclusive.

[0021] It is equally preferred that at least one polymeric chain of therotaxane is selected from the group of alternating and random copolymershaving at least one structure selected from the group consisting of:

[0022] wherein R₁, R₂, and R₃ are independently selected from the groupconsisting of hydrogen, alkyl groups, alkoxy groups, aromatic groups,and N(R)₂ where R is an alkyl group comprising from 1 to 16 carbonatoms, and wherein w is a value from 1 to about 100;

[0023] wherein R₁ and R₂ are each independently selected from the groupconsisting of hydrogen, alkyl groups, alkoxy groups, aromatic groups,spiroflourenes, and N(R)₂ where R is an alkyl group comprising from 1 to16 carbon atoms, wherein R₃ through R₈ are each independently selectedfrom the group consisting of hydrogen, alkyl groups, and alkoxy groups,and wherein w is a value from 1 to about 100;

[0024] wherein R₁-R₆ are each independently selected from the groupconsisting of hydrogen, alkyl groups, and alkoxy groups, and wherein wis a value from 1 to about 100;

[0025] wherein AR is an aromatic group and w is a value from 1 to about100; and

[0026] wherein w is a value from 1 to about 100.

[0027] It is preferred that at least one ring of the rotaxane isselected from the group consisting of: cyclodextrins, cyclophanes, ringscomprising

[0028] wherein AR is an aromatic group and w is a value from 1 to about100, rings comprising pyridine groups, and rings comprising quinolinegroups.

[0029] The present invention also includes a light emitting devicecomprising the light emitting polymeric material described above.

[0030] Other examples of synthetic methods are described in reference 27below.

[0031] These devices may be constructed in accordance with depositionand assembly techniques known in the art. The present invention may beused in the creation of a wide variety of lighting and lighted displays,giving the many advantages associated with polymeric materials.

[0032] In accordance with the present invention, results are presentedfor bilayer devices using PVK as a hole-transport layer and a family ofcopolymers of PPV and poly(pyridyl vinylene) PPyV with various sidegroups as the emitting layers. The absorption, photoluminescence andelectroluminescence spectra indicate that the PL and EL are attributedto the formation of an exciplex at the PVK/copolymer interface for allthe copolymer systems studied. An exciplex, like an excimer, is anexcited state complex, except that an exciplex is formed between twodifferent molecules (polymers in this case) rather than identical onesfor an excimer [19]. Contrary to expectations, earlier reported devicesdo not exhibit exciplex formation. For example, Greenham et al reporteda bilayer device with CN-PPV and PPV, but the EL matches the PL and ELof a single CN-PPV film [3]. Results for other bilayer configurationsalso do not support exciplex formation [2]. Osaheni and Jenekhe [20]have observed exciplex formation in bilayers of PBO and TTA, but onlyfor PL, although they do suggest that exciplexes may be importantprocesses in organic light-emitting devices [20-21]. PL and EL due toexciplex formation has been reported in blends of PVK and a multiblockcopolymer by Karasz and coworkers [17], but devices with separate layerswere not investigated.

BRIEF DESCRIPTION OF THE DRAWINGS

[0033]FIG. 1 depicts three chemical structures relevant to the presentinvention: (a) a copolymer of PPyV and PPV with side groups R=C₁₂H₂₅ orCOOC₁₂H₂₅, (b) a copolymer with side group R=OC₁₆H₃₃ and strapR₂=C₁₀H₂O, and (c) a hole-transport layer poly(vinyl carbazole).

[0034]FIG. 2 depicts plots showing absorbance of a single layer of PVK,a single layer of copolymer, and a bilayer of PVK/copolymer: (a)PPyVP(COOC₁₂H₂₅)₂V, (b) PPyVP(C₁₂H₂₅)₂V and (c) “strapped” copolymer.

[0035]FIG. 3 shows photoluminescence of (a) PPyVP(C₁₂H₂₅)₂V film (dashedline), PVK/PPyVP(C₁₂H₂₅)₂V bilayer film (solid line), PVK film (O) (b)PPyVP(COOC₁₂H₂₅)₂V film (dashed line), PVK/PPyVP(COOC₁₂H₂₅)₂V bilayerfilm (solid line), PVK film (O), and (c) strapped copolymer film (dashedline), PVK/strapped copolymer bilayer film (solid line), PVK film (O).

[0036]FIG. 4 shows electroluminescence (solid lines) for a (a)ITO/PVK/PPyVP(COOC₁₂H₂₅)₂V/AI device and a (b) ITO/PVK/strappedcopolymer/AI device, and photoluminescence (dashed lines) for bilayerfilms of PVK and (a) PPyVP(COOC₁₂H₂₅)₂V and (b) strapped copolymer.

[0037]FIG. 5 shows current density-voltage characteristics (O) andbrightness-voltage characteristics of an ITO/PVK/PPyVP(COOC₁₂H₂₅)₂V/AIdevice. Inset shows a comparison between a single layer,ITO/PPyVP(COOC₁₂H₂₅)₂V/AI, device (□) and the bilayer device (◯). Thebilayer device is 10 times brighter at 10 times lower current densityimplying a 100 times improvement in efficiency.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

[0038] In accordance with the foregoing summary of the invention, thefollowing presents a detailed description of the preferred embodiment ofthe invention which is presently considered to be its best mode.

[0039] The synthesis of the PPyVPV copolymers is described elsewhere[22]. FIG. 1(a) shows the molecular structure of poly(pyridyl vinylenephenylene vinylene) (PPyVPV). We report results for copolymers with sidegroups R=COOC₁₂H₂₅ and C₁₂H₂₅. FIG. 1(b) shows the same copolymer with a“strap” across the phenyl ring in alternate PPV segments. For the secondcopolymer the side groups are R₁=OC₁₆H₃₃ with a strap R₂=C₁₀H₂₂. Thecopolymers are soluble in common organic solvents such astetrahydrofuran (THF), xylene, and chloroform. The PVK (FIG. 1(c)) waspurchased from Aldrich Chemical Co.

[0040] The PL and EL measurements were made using a PTI QM1 luminescencespectrometer. The absorption measurements were made using a Perkin ElmerLambda 19 UV/Vis/NIR spectrometer. The current-voltage characteristicswere measured using two Keithley 195A multimeters. The voltage wasapplied using a HP 6218A dc power supply. Quantum efficiencymeasurements were made using a calibrated QTH lamp and a United DetectorTechnologies Silicon Photodiode (UV-100).

[0041] The samples for PL and absorption measurements were spin cast onquartz. PVK was spin cast (˜3000 rpms) from a 10 mg/ml solution in THF.The copolymers were all spin cast (˜1000 rpms) from xylene (˜10 mg/ml)so the underlying PVK layer was not dissolved. For devices the polymerswere spin cast on indium tin-oxide (ITO) substrates, which hadpreviously been cleaned. The PVK layer in the bilayer configurations wasdried for ˜30 seconds in a laminar flow hood before the copolymer layerwas spin cast. All fabrication steps for the devices were conducted inan ambient atmosphere in a Class 100 cleanroom. Aluminum electrodes werethermally evaporated onto the copolymer surface at low pressures (<10⁻⁶torr). The active area of the devices was 7 mm².

Results and Discussion

[0042]FIG. 2 shows the absorbance for single and bilayer systems. Eachof the plots shows the absorbance of a single layer of PVK, a singlelayer of a copolymer, and a bilayer configuration of PVK and thecorresponding copolymer. The onset of PVK absorption is at 3.5 eV andshows two spectral features at 3.6 and 3.75 eV similar to previousreports [6,7]. In each of the three cases (a), (b) and (c) of FIG. 2 theabsorbance of the bilayer configuration is the sum of the absorbance ofeach of the individual layers. No new ground to excited statetransitions are present. Photoluminescence excitation (PLE) results (notshown) for each of the systems confirm these results.

[0043] The photoluminescence for the single layer and bilayerconfigurations are shown in FIG. 3. The PL (excited at 3.6 eV) of a PVKfilm is shown in FIG. 3a, 3 b and 3 c by the open circles (O) and peaksat 3.05 eV similar to previous reports [6,7]. The dashed line is the PLof a single layer film of each copolymer, (a) PPyVP(C₁₂H₂₅)₂V, (b)PPyVP(COOC₁₂H₂₅)₂V and (c) the strapped copolymer. The spectra aresimilar with each of the peaks at ˜2.1 eV with the exception of thestrapped copolymer which also has a significant shoulder at 2.25 eV. ThePL of the copolymer films, which peak near 2.6 eV [23], aresignificantly redshifted from that of the solution PL (not shown). ThePL redshift from solution to film is due to aggregation in the copolymerfilms [23].

[0044] The solid lines in FIG. 3 are the PL spectra for the bilayerconfigurations of PVK and each of the copolymers. In each case thebilayer films were excited at 3.6 eV an energy that is greater than theband gap of PVK. In each case, more prominently in FIGS. 3b and 3 c,there is PL emission at the same energy as the PVK PL emission (3.1 eV).However, the main feature in the PL of the bilayer films is located at2.5 eV for (a) PPyVP(C₁₂H₂₅)₂V and (b) PPyVP(COOC₁₂H₂₅)₂V and at 2.4 eVfor the (c) strapped copolymer. Emission at these energies is notobserved for individual films of either PVK or the copolymers indicatingthat the emission is due to a completely different species, theexciplex. When the excitation energy is lowered below 3.4 eV (band gapof PVK) the emission due to the exciplex is drastically reduced. Inaddition, varying the concentration or thickness of the copolymer or PVKfilms in the bilayer configuration will change the relative strengths ofthe exciplex peak and PVK peak.

[0045] PPyVP(C₁₂H₂₅)₂V and PPyVP(COOC₁₂H₂₅)₂V have nearly identical PLresults, which is expected since the side chains tend to perform thesame function in both copolymers. The single layer PL results for thestrapped copolymer in FIG. 3c show a completely new feature, a highenergy shoulder. The high energy shoulder is closer to the solution PLand is attributed to unaggregated sites in the film. The C₁₀H₂₀ straparound every other phenyl ring tends to disturb the aggregation thatoccurs in the other copolymers of this family. The same shoulder (now onthe low energy side) also appears in the bilayer film, indicating the PLhas contributions from exciplex sites and from unaggregated regions ofthe strapped copolymer.

[0046] The bilayer devices have turn-on voltages ˜12-16 volts withcurrent densities between 0.1 and 0.5 mA/mm². The devices can easily beseen in a brightly lit room and have internal quantum efficiencies˜0.1-0.5%. FIG. 5 shows the current-voltage (◯) and voltage-brightness(solid line) characteristics for a typical ITO/PVK/PPyVP(COOC₁₂H₂₅)₂V/AIbilayer device. The inset of FIG. 5 shows a comparison between a singlelayer device (ITO/PPyVP(COOC₁₂H₂₅)₂V/AI) and the bilayer device shown inthe main plot. The bilayer device is ten times brighter at an order ofmagnitude lower current density which means the bilayer device is −100times more efficient than the single layer device.

[0047] In the devices the electrons are injected from the AI electrodeinto the conduction band of the copolymer, but they are confined at thePVK/copolymer interface due to a large barrier. The holes injected fromthe ITO also may be confined at the interface by a somewhat smallerbarrier. The increased number of electrons and holes in the interfaceregion increase the probability of recombination via exciplex emission.In addition the buried interface severely reduces the non-radiativerecombination that otherwise will occur near the electrodes.

CONCLUSION

[0048] In summary, the present invention demonstrates the presence ofexciplex emission in heterojunctions of PVK and PPyVP(R)₂V. The additionof a C₁₀H₂₀ strap on every other phenyl ring in the copolymer reducesthe aggregation in the films. Emission from the strapped copolymerbilayers is a combination of light from exciplex and unaggregated sites.The exciplex is the primary method of electroluminescence in the bilayerdevices. The bilayer devices we have fabricated show a 100 timesincrease in efficiency compared to single layer devices due to chargeconfinement and exciplex emission at the interface.

[0049] The following references are hereby incorporated herein byreference:

REFERENCES

[0050] [1] J. H. Burroughes, D. D. C. Bradley, A. R. Brown, R. N. Marks,K. Mackay, R. H. Friend, P. L. Burns, & A. B. Holmes, Nature, 347 (1990)539.

[0051] [2] A. R. Brown, D. D. C. Bradley, J. H. Burroughes, R. H.Friend, N. C. Greenham, P. L. Burn, A. B. Holmes, and A. Kraft, Appl.Phys. Lett. 61 (1992) 2793.

[0052] [3] N. C. Greenham, S. C. Moratti, D. D. C. Bradley, R. H.Friend, and A. B. Holmes, Nature, 365 (1993) 628.

[0053] [4] H. Vestweber, A. Greiner, U. Lemmer, R. F. Mahrt, R. Richert,W. Heitz, and H. Bassler, Adv. Mater. 4 (1992) 661.

[0054] [5] G. Grem, G. Leditzky, B. Ulrich, and G. Leising, Adv. Mater.4 (1992) 36.

[0055] [6] J. Gruner, P. J. Hamer, R. H. Friend, H-J. Huber, U. Scherf,and A. B. Holmes, Adv. Mater. 6 (1994) 748.

[0056] [7] Y. Yang, Q. Pei, and A. J. Heeger, J. Appl. Phys. 79 (1996)934.

[0057] [8] Y. Ohmori, M. Uchida, K. Muro, and K. Yoshino, Sol. St. Comm.80 (1991) 605.

[0058] [9] Y. Ohmori, C. Morishima, M. Uchida, K. Yoshino, Jpn. J. Appl.Phys. 31 (1992) L568.

[0059] [10] I. D. Parker, Q. Pei and M. Marrocco, Appl. Phys. Lett. 65(1994) 1272.

[0060] [11] D. D. Gebler, Y. Z. Wang, J. W. Blatchford, S. W. Jessen,L-B. Lin, T. L. Gustafson, H. L. Wang, T. M. Swager, A. G. MacDiarmid,and A. J. Epstein, J. Appl. Phys. 78 (1995) 4264.

[0061] [12] Y. Z. Wang, D. D. Gebler, L. B. Lin, J. W. Blatchford, S. W.Jessen, H. L. Wang, A. J. Epstein, Appl. Phys. Lett. 68 (1996) 894.

[0062] [13] J. Tian, C-C. Wu, M. E. Thompson, J. C. Sturm, R. A.Register, Chem. Mater. 7 (1995) 2190.

[0063] [14] M. Onoda, J. Appl. Phys. 78 (1995) 1327.

[0064] [15] C. W. Tang and S. A. VanSlyke, Appl. Phys. Lett. 51 (1987)913.

[0065] [16] R. H. Partridge, Polyme, 24 (1983) 733-782.

[0066] [17] B. Hu, Z. Yang, and F. E. Karasz, J. Appl. Phys. 76 (1994)2419.

[0067] [18] C. Zhang, H. von Seggern, K. Pakbaz, B. Kraabel, H-W. Scmidtand A. J. Heeger, Synth. Met. 62 (1994) 35.

[0068] [19] M. Pope and C. E. Swenberg, Electronic processes in organiccrystals. (Oxford University Press, New York, 1982), 739.

[0069] [20] J. A. Osaheni and S. A. Jenekhe, Macromol. 27 (1994) 739.

[0070] [21] S. A. Jenekhe and J. A. Osaheni, Science, 265 (1994) 765.

[0071] [22] D-K. Fu and T. M. Swager, Poly(Pyridyl Vinylene PhenyleneVinylene)s: Synthesis and Solid State Organizations, to be published;copy enclosed.

[0072] [23] J. W. Blatchford, S. W. Jessen, T. M. Swager, A. G.MacDiarmid, A. J. Epstein, Phys. Rev. B, (1996) in press.

[0073] [24] Y. Z. Wang, D. D. Gebler, T. M. Swager, D-K. Fu, A. G.MacDiarmid, A. J. Epstein.

[0074] The contents of U.S. Provisional Patent Application Serial No.60/023,071 are hereby incorporated herein by reference.

[0075] In view of the present disclosure or through practice of thepresent invention, it will be within the ability of one of ordinaryskill to make modifications to the present invention, such as throughthe use of equivalent arrangements and compositions, in order topractice the invention without departing from the spirit of theinvention as reflected in the appended claims.

What is claimed is:
 1. A light emitting polymeric material said lightemitting polymeric material capable of producing electroluminescenceupon being provided with a flow of electrons, said light emittingpolymeric material comprising: a plurality of polymeric chainscomprising polymeric chains each having substituent moieties ofsufficient number and size and extending from said polymeric chain andabout a substantial portion of the circumference about said polymerchain so as to maintain said polymeric chains in a sufficientlydeaggregated state, so as to substantially prevent the redshifting ofsaid electroluminescence and the lowering of light emission efficiencyof said electroluminescence.
 2. A light emitting polymeric materialaccording to claim 1 comprising polymeric chains selected from the groupconsisting of alternating and random copolymers, having the structure:

wherein m is the degree of polymerization; Y is selected from the groupconsisting of —CH₂, O, S, CO and NR₂ wherein R is an alkyl groupcontaining 1 to 16 carbon atoms; wherein A and C are independentlyselected from the group consisting of (CH₂)_(n), (CH₂CH₂O)_(n), (CH₂CH₂O)_(n)NR; wherein R is an alkyl group containing 1 to 16 carbonatoms, and aryl groups having 6 to 14 carbon atoms; B is selected fromthe group consisting of (CH₂)n, aryl groups having 6 to 14 carbon atoms,and calixarenes having 18 to 200 carbon atoms; wherein u may be of avalue independently selected from the group 1 to 6, inclusive; wherein wmay be of a value independently selected from the group 1 to 6,inclusive; wherein n may be of a value independently selected from thegroup 0 to 6, inclusive; and wherein Z may be a structure selected fromthe group consisting of:

wherein R is an alkyl group containing 1 to 16 carbon atoms; wherein Yis selected from the group consisting of —CH₂, O, S, CO and NR₂ whereinR is an alkyl group containing 1 to 16 carbon atoms; B is selected fromthe group consisting of (CH₂)_(n), aryl groups having 6 to 14 carbonatoms, and calixarene having 18 to 200 carbon atoms; wherein u may be ofa value independently selected from the group 1 to 6, inclusive; andwherein w may be of a value independently selected from the group 1 to6, inclusive.
 3. A light emitting polymeric material according to claim1 wherein said polymeric material is further provided with a layer of anelectron blocking polymer.
 4. A light emitting polymeric materialaccording to claim 3 wherein said electron blocking polymer is selectedfrom the group consisting of poly(vinylcarbazole).
 5. A light emittingdevice, said device comprising a light emitting polymeric materialaccording to claim 1, and a source of electrical current so as to supplysaid electron transporting polymer with a flow of electrons.
 6. A lightemitting device, said device comprising a light emitting polymericmaterial according to claim 1, and a source of electrical current so asto supply said electron transporting polymer with a flow of electrons,said device selected from the group consisting of single layer, bilayerand multi-layer light emitting devices.
 7. A light emitting polymericmaterial said light emitting polymeric material capable of producingelectroluminescence upon being provided with a flow of electrons, saidlight emitting polymeric material comprising: a plurality of polymericchains comprising polymeric chains each being provided with rotaxenes ofsufficient number and size and extending from said polymeric chain andabout a substantial portion of the circumference about said polymerchain so as to maintain said polymeric chains in a sufficientlydeaggregated state, so as to substantially prevent the redshifting ofsaid electroluminescence and the lowering of light emission efficiencyof said electroluminescence.
 8. A light emitting polymeric materialaccording to claim 7 wherein said polymeric material is further providedwith a layer of an electron blocking polymer.
 9. A light emittingpolymeric material according to claim 8 wherein said electron blockingpolymer is selected from the group consisting of poly(vinylcarbazole).10. A light emitting device, said device comprising a light emittingpolymeric material according to claim 7, and a source of electricalcurrent so as to supply said electron transporting polymer with a flowof electrons.